New evidence of bones used as fuel in the Gravettian level at Coímbre cave, northern Iberian Peninsula

The use of bone as fuel has been already documented in some sites dated to the Middle and Upper Palaeolithic. They contribute to a longer combustion time due to their durability; consequently, they are useful to reduce the need for firewood, a good advantage in open palaeoenvironmental contexts with limited arboreal vegetation. The use of bones as fuel can be identified by several lines of evidence. The main one is a large number of burned bones, with an intense cremation–charring or calcination, together with high fragmentation resulting from the long contact with the fire. Other features may be present, although they can also result from individual circumstances. They include either the presence of complete skeletal profiles–which implies using all the bones of the animal–or a selection of the anatomical parts which contribute better to combustion, i.e. epiphyses and axial elements. In this article, we argue that the faunal assemblage of level Co.B.6 of Coímbre cave fully corresponds to this model. Moreover, this level coincides with a cold palaeoclimatic event, which was correlative to the climatic deterioration that occurred at the end of MIS 3, and an open environment. Thus, we propose that this level contains the first known use of bones as fuel in the Cantabrian Gravettian